Peri-Operative Management of Patients Undergoing Laparoscopic Colorectal Surgery

Inclusion Criteria: * Patients with colorectal disease that requires a bowel resection who agree to have laparoscopic surgery with placement of an oesophageal doppler and a central line and who agree to be randomised with regards to a post operative analgesic regime. Exclusion Criteria: * Patients will be excluded from the post operative analgesia trial if they have abnormal clotting, skin infection over or near the back, presence of neurological disorders or anatomical abnormalities of the vertebral column, or for a reason identified by the anaesthetist. * Patients will also be excluded if there is a contra-indication to oesophageal doppler such as oesophageal disease, recent oesophageal or upper airway surgery, moderate to severe aortic valve disease and bleeding diathesis.